The present invention generally relates to laser-based optical systems and methods for laser-based measurement and alignment and, more particularly, to a laser alignment tool including a low-power, line laser and a one-dimensional electronic target, and a method for laser alignment.
Laser alignment and measurement are standard techniques in industrial maintenance and operation. In general, a laser is used for alignment by making it parallel to reference points and using a target to measure deviations from those points. Precision laser alignment tools can be used for maintenance, repair, quality control, and the like in virtually any industry. Commercial products are available for a variety of alignment and measurement tasks in industries such as aerospace, automotive, power generation, shipbuilding, steel manufacturing, and numerous others. Especially, the manufacture of aircraft presents many challenges in the field of laser alignment.
Companies like Hamar Laser, Pinpoint Laser Systems, and Pro Shot, Inc., have developed wireless target technologies that rid the aircraft of cables, allowing tasks to be performed without the burden of wires cluttering the work area, easing setup and operating tasks. Still, laser-based optical systems for measurement and alignment that are available on the commercial market for use in the aerospace industry are relatively large, complicated and expensive.
Further, commercially available laser alignment tools used in the aerospace industry use a point laser or a rotating point laser as an aiming laser or transmitter. Since the round spot of a point laser may or may not have a Gaussian profile, variations in readings and errors may occur. Also, the rotating laser design is relatively complicated because of the rotating parts. Therefore, these components are prone to failure.
Commercially available laser alignment tools used in the aerospace industry typically comprise a laser receiver, which features a digital display. The digital displays are often difficult to discern from a distance, and not optimized to indicate whether or not an alignment is in or out of design tolerance. A laser receiver manufactured by Pro Shot, Inc. provides an LED display on its backside and audio tones in addition to an LCD front panel. This laser receiver works with a Pro Shot laser transmitter, and most other brands of rotating lasers on the market. The LED display of the Pro Shot laser receiver provides five channels of information: high, high fine, on grade, low fine, and low, as needed for an electronic level. Since the LED display is not programmable, only tolerances for one grading/leveling application can be displayed. Further, the LED display cannot be physically modified and is, therefore, limited to a given application. Although the user can select between three operating accuraciesxe2x80x94ultra-fine, standard, and coarsexe2x80x94the Pro Shot laser assembly does not reach the accuracy that is needed for certain applications in the aerospace industry.
There has, therefore, arisen a need for the development of a laser alignment tool that is suitable for specific alignment tasks in the aerospace industry, such as the centering of an airplane rudder during the actuator shimming process, but is flexible enough to be used for a variety of alignment tasks in various industries. There has also arisen a need to modify the aiming laser to avoid the disadvantages of a point or rotating point laser. There has further arisen a need to modify the laser receiver or electronic target to make it more visible from the distance and adjustable to different alignment tasks as needed. There has still further arisen a need for a laser alignment tool that is compact and lightweight to avoid possible damage to the aircraft or personal injuries and for easy handling.
As can be seen, there is a need for a laser alignment tool suitable for specific alignment tasks in the aerospace industry and for a method for laser alignment having a very high measurement accuracy and reliability. Also, there is a need for a laser alignment tool that is compact, light weight and portable, and that is relatively inexpensive. Moreover, there is a need for a modified laser assembly to be paired with an electronic target that can be adjusted to different alignment tasks.
The present invention provides a laser alignment tool suitable for, but not limited to, specific alignments tasks in the aerospace industry. The present invention also provides a method for laser alignment having a very high measurement accuracy and reliability. The present invention further provides a laser alignment tool that is compact, lightweight, and portable, and that is relatively inexpensive. Moreover, the present invention provides a line laser assembly to be paired with an electronic target that can be adjusted to different alignment tasks.
In one aspect of the present invention, a laser alignment tool comprises a line laser assembly including a laser for emitting a laser beam line; and an electronic target assembly including a photo detector array. The laser beam line of the laser is pointed toward a center of the photo detector array with a longitudinal axis of the laser beam line being perpendicular to the centerline of the photo detector array.
In another aspect of the present invention, a laser alignment tool includes a line laser assembly positioned inside a rigid enclosure mounted to a reference location, and an electronic target assembly having a target housing mounted to a part to be aligned.
In still another aspect of the present invention, a line laser assembly includes a tilt stage, a laser diode mounted onto the tilt stage, a line-generating lens, and a lens holder positioning the line-generating lens in front of the laser diode.
In yet another aspect of the present invention, an electronic target includes a visual indication panel having an aperture and including a discrete LED display, a photo detector array, a narrow band pass filter positioned between the aperture of the visual indication panel and the photo detector array, and a programmable microprocessor.
In a further aspect of the present invention, a method of laser alignment includes the steps of: providing a laser alignment tool including a line laser assembly and an electronic target assembly; mounting the line laser assembly to a reference location; programming a microprocessor with a variable range for each LED of a discrete LED display; mounting the electronic target assembly to a part to be aligned; pointing a laser beam line toward the center of a photo detector array with the longitudinal axis of the laser beam line being perpendicular to the centerline of the photo detector array; reading measurement results from the discrete LED display; and aligning the part to required accuracy.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.